Async Methods

waitFor

The waitFor query is used when we need to wait for our expectations to pass. The async wait utilities allow the system to wait for an assertion before proceeding forward. The async wait utility will keep retrying until the condition is satisfied or time runs out.

Here is an example of the waitFor query,

test('Wait For Example', async () => {
  // element is initially not present in the application
  // function will wait for the appearance and return the element
  await waitFor(() => {
    expect(getByText('Random Element')).toBeInTheDocument()
  })
})

The default interval in the waitFor query is 50 ms, and the timeout is 1000ms. These default settings can be changed while writing the code. 

waitForElementToBeRemoved

The waitForElementToBeRemoved is used to wait for an element to disappear. Similar to waitFor method, the waitForElementToBeRemoved method allows the system to wait for an assertion before proceeding forward. The waitForElementToBeRemoved method will keep retrying until the condition is satisfied or time runs out.

The following example waits for an element to disappear using the waitForElementToBeRemoved method.

test('Disappearance Example', async () => {
  // element is removed
  await waitForElementToBeRemoved(() => queryByText('Item to Disappear'))
})

FAQs

1. What are Testing Libraries?
   Testing Libraries are a collection of libraries for testing applications. These libraries provide assurance to the developer that the application will work as expected in a real-case scenario.
2. What is Jest?
   Jest is a framework in JavaScript that is used for the testing purposes of large web applications. It is maintained by Facebook. Since Jest doesn’t require a lot of configuration, it is an excellent option to be used as a testing framework among new developers.
3. What is the disadvantage of using Jest?
   Although Jest is a compelling library, it is comparatively prolonged compared to other testing libraries.
4. What is DOM?
   DOM stands for Document Object Model. It is a cross-platform and language-independent interface for treating an XML or HTML document.
5. What is Dynamic Testing?
   A Dynamic Test is one of the most commonly used tests, and it is generated at the run time. We use the TestFactory method to generate Dynamic Tests in JUnit5. TestFactory method is a non-static and non-private method.

Key Takeaways

This Blog covered all the necessary points about the async methods in Testing libraries. We further looked at three async methods and looked at how to implement them using the Testing Libraries.

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